How to wind a perfect coil condenser...

[dixiedrifter]

Ok thought I would do a quick tutorial on how to wind coils. First you need a jig. Mine is pretty simple, a 1/2" black iron pipe run thru a couple 7/8th bearings bolted down to a table with a pillow block. There are three eye bolts installed near the end to ensure that the coil gets plenty of grip when turning.

Step one. Using a small tubing bender from harbor freight, put a slightly less than 90 degree bend in the tubing and run it thru the eye bolts.





Step two: After running the tubing thru the bols, turn the eye bolts at an angle to better grip the tubing and screw them into place.





Step three: This is the second most difficult part after the final bend after coiling. Slowly start the tubing around the mandrel while holding it down to keep it from kinking. Once you get this one down it gets a lot easier.





Step four keep turning:





Step five: Keep on turning while allowing about an 1/8" on an inch of space between the tubing... keep holding down so the tubing doesn't kink.




Step six: Once you get the inner coil as long as you want it, it is time to start the outer coil. However again you need space between the tubing for maximum effect. To accomplish this I used a notebook cover would around the inner coil and secured with some sacrificial zip ties. To start the coil around the tube simply pull it over and turn while holding down.





Step 7: More winding.





Step 8: At this point I decided to add on some cardboard tubing to increase the final diameter of the coil to better match the exterior of 2" copper tubing using exactly one round of cardboard. I recommend a 50-50 mix of notebook/cardboard to create a dual size coil.





Step 9: When you get to the end, be sure to leave about an inch unwrapped. This will allow your uptubes to fit better. This is the really tricky part... if you can get this done your home free. I bent the tubing carefullly with the benders and then finished up with some channel locks and the spring bender.









Step 10: Cleanup of copper. Soak in warm Rid-X or weak lye solution for about one hour then take it down to the local car wash and blow out the cardboad with the pressure wand.


Final fit pics:









Well thats how it is done. No salt or other BS just a nice clean coil.


Attention: I will soon be offering these coils for sale for $50 each plus shipping anywhere in the USA. While very easy to wind as shown above, keep in mind that there is a bit of a learning curve. It can take hours to build a jig, if you screw up winding one at any point and you have to start all over again from scratch, and its a one shot affair... you only need one coil that should last a lifetime. Time and materials can easily add up to more than the price I am asking. If your interested in purchasing one already completed, drop me PM for details... I take Paypal and will be happy to list it on Ebay.

[ZeroGee]

Damn, DD, that's downright gorgeous! Great design, excellent pics and careful explanation for those of us less fumble-fingered -- and an offer to sell to those of us who can barely get our keys in the ignition (take that however you like).

Really -- good job!!

Cheers!

[grunger]

very nice.

[Bubba]

That's a great tutorial

[Rebel_Yell]

Great tutorial Dixiedrifter. How much copper did this require?

[snuffy]

Classic. This should be a sticky.

[punkin]

Classic. This should be a sticky.

I've put it in a threads of note and stickied that to the top. Just stops the clutter.

[Hogetveit]

Nice!

[adama]

Great tute dixiedrifter.
Great to see it all laid out in pictures . . . I needs the pictures.

[minime]

That's one gorgeous coil!

To get rid of the cardboard I just sat the coil in the BBQ for 5 minutes and then tossed it into the dishwasher.

[NineInchNails]

Very nice pictorial dixiedrifter!
What is this spring that is shown in this pic? Do ya think that this is necessary or was it used just as a precaution?

[Disobedierudite]

What is this spring that is shown in this pic? Do ya think that this is necessary or was it used just as a precaution?

I was just looking at a set of those in Home Depot last night. That spring is a tube bender/kink preventer. If you bend the tube while inside the spring, the sides of the tube won't kink because the spring stays circular inside and is stronger than the copper tubing. It basically keeps the tubing round while you bend it. They were $9 for a set of three sizes. I hesitated to buy it because I only needed 1/4 for this purpose.

BTW, DD, that's an awesome plan and explanation. I'm planning on using it for both the reflux condenser and a Graham Condenser.

[NineInchNails]

What is this spring that is shown in this pic? Do ya think that this is necessary or was it used just as a precaution?

I was just looking at a set of those in Home Depot last night. That spring is a tube bender/kink preventer. If you bend the tube while inside the spring, the sides of the tube won't kink because the spring stays circular inside and is stronger than the copper tubing. It basically keeps the tubing round while you bend it. They were $9 for a set of three sizes. I hesitated to buy it because I only needed 1/4 for this purpose.

BTW, DD, that's an awesome plan and explanation. I'm planning on using it for both the reflux condenser and a Graham Condenser.

Ahhhh ok. Thanks. I just now realized that the spring was in every pic. Duhhhh . Looks like it's a worth while investment.

[dsmith1997]

Are these coils really available for sale? Debating buying one of yours versus wasting a lot of copper from no experience and an appropriate place to attempt this?

Duane

[Oracle]

I tried my hand at making a double coil condenser, having been inspired by both Dixiedrifter’s and Hook’s tutorials. I have not been able to locate a local source for the thick-walled ¼” copper tubing, so opted for the cheap refrigeration ¼” tubing that comes in a kit for hooking up icemakers. You can get a kit for $15 (~15’) or for $20 you can get a 25’ length (enough for 2 tries). I am an optimistic sort, so went with the $15 kit. I chopped off about 2 feet to play with. As mentioned above, the tubing bends nicely with the tubing bender (Harbor Freight tool), but when I tried to wind it using the jig I assembled, it flattened out like a tapeworm. Disgusting!

I decided then and there that I would brave the challenge of a salt-filled tube to avoid the flattening. With much appreciated help from one of my offspring (and a small funnel attached using some tape), I filled the remaining 12+ feet of tubing with salt. Basically, I stretched the coil of tubing so that it looked like a “slinky” about 5 feet tall, but not significantly uncoiled. I pinched the bottom with some needle-nosed pliers and tapped the tubing while salt was slowly poured into the funnel above. When full, I “threaded” the open end into the eyelets of the jig and then pinched that end closed. The entire jig was super cheap, made of ½” pvc pipe, a T-joint, and a couple of pipe “hangers” made of plastic (the latter substituted for the pillow block bearings). The assembly was mounted on a 2” x 4” piece of lumber and clamped to my work table. This let me keep the tubing coiled while I used the jig (see pics). I wasn’t sure this would work, that is I was afraid the pvc parts might break or bend too much while I turned the tubing. Worked like a charm. No trouble with the copper tube flattening. I used a cardboard tube (from a paper towel roll) to cover the inner coil when winding the outer coil. Zip ties held the paper tube in place as I worked. As recommended by rad, I used a length of coated wire (an old USB cable) as a spacer for the tube winding.

Jig assembly with partial inner coil

Inner_coil_1.JPG (37.08 KiB) Viewed 11030 times

Jig assembly showing outer coil (and spacer wire)

Outer_coil_1.JPG (36.57 KiB) Viewed 10983 times

Jig assembly showing inner/outer coil/cardboard/salt

Outer_coil_2.JPG (33.45 KiB) Viewed 10943 times

When it was done, I cut the pinched end of the tubing (see spilled salt) in order to get the tubing free of the “eyelets”. I used needle-nosed pliers to remove the paper towel layer (no soaking needed). After cutting off the other pinched end, I then set about tapping and shaking the coil to knock out as much salt as possible. Humidity was low, so caking was not a problem. I could not get all of the salt out (a lot did come out though), so hooked up the coil to the garden hose/faucet outside. I adjusted the pressure so it wouldn’t blow the hose off and let it go for about an hour. A few taps along the way and it started dripping. Soon it was flowing fine and the salt was gone. After assembling the condenser, I hooked it up to my pump/radiator system and measured the maximum flow rate at about 1.5 liters per minute. Happy I am.

Thanks again to all who have inspired me, not just the venerable Dixiedrifter and Hook!